ARBOCEL® CE

for PVC - production (suspension polymerization)

Polyvinyl
Chloride (PVC) is one of the most widely used thermoplastic polymers which is
often used e.g. in building industry. PVC is highly resistant to other chemical
products and can be easily mixed with many additives in order to adjust its
properties. PVC is produced with different degrees of polymerisation. One
differs between rigid PVC and flexible PVC.

There are several processes for producing PVC, one of which is suspension
polymerization.
In this process, a vinyl chloride monomer is dispersed in water by vigorous
agitation.
The addition of suspension stabilizing agents lowers the coalescence of the
forming vinyl chloride droplets and adjusts the particle sizes of the monomer
droplets as well as the particle sizes and porosity of the PVC after
polymerization.

HPMC - Hydroxypropyl Methyl Cellulose (ARBOCEL® CE) is beside
Polyvinylalcohol (PVA) one of the most commonly used suspension agents.

ARBOCEL® CE helps to control particle sizes, allows uniform particle
size distribution and influences the porosity. The porosity of the polymer
particles is strongly linked to the property to adsorb additives like e.g.
plasticizers or stabilizers which finally lead to the demanded properties of
the polymer during processing and for the final product.

PVC particles produced by this method show particle sizes of 50 to 300 μ m.
The grains have a smooth surface and irregular shape. They show a porous
interior, with primary particles of 1 - 3 μ m
in size. The exterior is covered by a skin or membrane of 0.5 -1.0 μ m
thickness and consists mostly of PVC. This peculiar and complex morphology is
due to the insolubility of PVC in its own monomer.

Ultra low viscous ARBOCEL® CE is the most suitable product for PVC
manufacturing processes. Methoxy and hydroxypropyl substitution levels and the
viscosity determine the performance characteristics as a PVC suspending agent.
Besides this, the particle size of the HPMC powders are specially designed to
dissolve perfectly for a smooth production.